We are calling the checksum helper after the dma_map_single()
call to map the packet. This is incorrect as the checksumming
code will touch the packet from the CPU. This means the cache
won't be properly flushes (or the bounce buffering will leave
us with the unmodified packet to DMA).
This moves the calculation of the checksum & vlan tags to
before the DMA mapping.
This also has the side effect of fixing another bug: If the
checksum helper fails, we goto "drop" to drop the packet, which
will not unmap the DMA mapping.
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Fixes: 05690d633f30 ftgmac100: Upgrade to NETIF_F_HW_CSUM
CC: [email protected] [v4.12+]
---
drivers/net/ethernet/faraday/ftgmac100.c | 25 ++++++++++++------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 9b7af94a40bb..96e9565f1e08 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -727,6 +727,18 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb,
*/
nfrags = skb_shinfo(skb)->nr_frags;
+ /* Setup HW checksumming */
+ csum_vlan = 0;
+ if (skb->ip_summed == CHECKSUM_PARTIAL &&
+ !ftgmac100_prep_tx_csum(skb, &csum_vlan))
+ goto drop;
+
+ /* Add VLAN tag */
+ if (skb_vlan_tag_present(skb)) {
+ csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG;
+ csum_vlan |= skb_vlan_tag_get(skb) & 0xffff;
+ }
+
/* Get header len */
len = skb_headlen(skb);
@@ -753,19 +765,6 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb,
if (nfrags == 0)
f_ctl_stat |= FTGMAC100_TXDES0_LTS;
txdes->txdes3 = cpu_to_le32(map);
-
- /* Setup HW checksumming */
- csum_vlan = 0;
- if (skb->ip_summed == CHECKSUM_PARTIAL &&
- !ftgmac100_prep_tx_csum(skb, &csum_vlan))
- goto drop;
-
- /* Add VLAN tag */
- if (skb_vlan_tag_present(skb)) {
- csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG;
- csum_vlan |= skb_vlan_tag_get(skb) & 0xffff;
- }
-
txdes->txdes1 = cpu_to_le32(csum_vlan);
/* Next descriptor */
Looks good to me. And I have tested it. It works perfectly fine.
Reviewed-by: Vijay Khemka <[email protected]>
Tested-by: Vijay Khemka <[email protected]>
On 10/24/19, 7:47 PM, "Benjamin Herrenschmidt" <[email protected]> wrote:
We are calling the checksum helper after the dma_map_single()
call to map the packet. This is incorrect as the checksumming
code will touch the packet from the CPU. This means the cache
won't be properly flushes (or the bounce buffering will leave
us with the unmodified packet to DMA).
This moves the calculation of the checksum & vlan tags to
before the DMA mapping.
This also has the side effect of fixing another bug: If the
checksum helper fails, we goto "drop" to drop the packet, which
will not unmap the DMA mapping.
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Fixes: 05690d633f30 ftgmac100: Upgrade to NETIF_F_HW_CSUM
CC: [email protected] [v4.12+]
---
drivers/net/ethernet/faraday/ftgmac100.c | 25 ++++++++++++------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 9b7af94a40bb..96e9565f1e08 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -727,6 +727,18 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb,
*/
nfrags = skb_shinfo(skb)->nr_frags;
+ /* Setup HW checksumming */
+ csum_vlan = 0;
+ if (skb->ip_summed == CHECKSUM_PARTIAL &&
+ !ftgmac100_prep_tx_csum(skb, &csum_vlan))
+ goto drop;
+
+ /* Add VLAN tag */
+ if (skb_vlan_tag_present(skb)) {
+ csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG;
+ csum_vlan |= skb_vlan_tag_get(skb) & 0xffff;
+ }
+
/* Get header len */
len = skb_headlen(skb);
@@ -753,19 +765,6 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb,
if (nfrags == 0)
f_ctl_stat |= FTGMAC100_TXDES0_LTS;
txdes->txdes3 = cpu_to_le32(map);
-
- /* Setup HW checksumming */
- csum_vlan = 0;
- if (skb->ip_summed == CHECKSUM_PARTIAL &&
- !ftgmac100_prep_tx_csum(skb, &csum_vlan))
- goto drop;
-
- /* Add VLAN tag */
- if (skb_vlan_tag_present(skb)) {
- csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG;
- csum_vlan |= skb_vlan_tag_get(skb) & 0xffff;
- }
-
txdes->txdes1 = cpu_to_le32(csum_vlan);
/* Next descriptor */
From: Benjamin Herrenschmidt <[email protected]>
Date: Fri, 25 Oct 2019 13:47:24 +1100
> Signed-off-by: Benjamin Herrenschmidt <[email protected]>
> Fixes: 05690d633f30 ftgmac100: Upgrade to NETIF_F_HW_CSUM
Please put the commit header string inside double quotes and parenthesis
(" ")
> CC: [email protected] [v4.12+]
Do not CC: stable for networking submissions as per the netdev FAQ.
All fixed up, and queued up for -stable, thanks Ben.
On Mon, 2019-10-28 at 16:24 -0700, David Miller wrote:
> From: Benjamin Herrenschmidt <[email protected]>
> Date: Fri, 25 Oct 2019 13:47:24 +1100
>
> > Signed-off-by: Benjamin Herrenschmidt <[email protected]>
> > Fixes: 05690d633f30 ftgmac100: Upgrade to NETIF_F_HW_CSUM
>
> Please put the commit header string inside double quotes and
> parenthesis
> (" ")
Will do next time, I had just copy/pasted the git shortlog :-)
> > CC: [email protected] [v4.12+]
>
> Do not CC: stable for networking submissions as per the netdev FAQ.
Ah oops, learned.
> All fixed up, and queued up for -stable, thanks Ben.
Thanks.
Cheers,
Ben.